Updated 2015-10-10: Paul suggests that this can also be accomplished by editing or creating
/usr/share/lightdm/lightdm.conf/50xserver-command.conf and adding the command
xerver-command=X -core -dpi 150. I haven't tried this myself. Alternatively, you can just use Xubuntu instead, which seems to run just as well, and has a handy UI for adjusting DPI. It also handles multi-monitor setups much better.
If you've tried to use Lubuntu (or LXDE on another distribution) with a high-DPI display, you've probably noticed that fonts and other UI elements are so tiny as to be illegible without a magnifying glass. You've probably also noticed that there is no GUI with which to adjust the UI scaling factor. Happily, it is possible to change the DPI settings in LXDE, but this being Linux, it requires editing obscure configuration files. Here's what you'll need to do:
- In your home directory, create a new text file named
- In this file, enter your desired DPI in the following format:
- Restart the X server. You can do this by pressing
Ctrl + Alt + F1to enter single-user mode, then running
sudo service lightdm stop, and then
sudo service lightdm start. (Note that it may be a different service if you are not running Lubuntu. Alternatively, you can just reboot your machine.)
This will scale UI elements in most, but not all, applications. For instance, it doesn't resize the desktop panel, so you'll likely want to do that as well. Luckily you can do so easily by right clicking on an empty space on the panel and selecting Panel Settings; from there, just change the height of the panel in pixels to a suitable value.
This is yet another tip that I'm posting mainly becuase it took me an inordinate amount of time to figure out how to do it. I found many suggestions on how to enable scaling, but none of them worked until I stumbled across the above instructions on the blog of bebabi34. His blog is in Italian, so naturally it's not very searchable for English speakers; hopefully by reproducing his instructions here, I can save others some time.